Air-blast heater.



E. HOHMANN.

AIR BLAST HEATER, APPLICATION FILED AUG.31, 1911.

m 79 75 27 J2 J7 33 77 Patented Sept. 17,1912.

V Unrran EDMUND HOHMANN, 0F STETIIN, GERMANY, ASSIGETP J FABRIK ACTIEN-GESELLSCHAFT VQBM. DEDIER, il

BATION OE? GEB'E-EANY.

AIR-B33155 To all whom it may concern Be it known that I, EDMUND HOHMANN, a subject of the German Emperor, and resident of Stettin, Germany, have invented certain new and useful Improvements in Air-Blast Heaters, of which the following is a specification.-

My present invention relates to air-blast heaters, particularly to those having nested annular chambers, and is intended for usecspeoially in connection with blast furnaces.

According to my invention radial partitions are provided in the nested annular chambers serving alternately to convey. first inwardly vgas and air for supporting combustion and then in opposite direction the air for the hotblast. These partitions sub-" divide the annular chambers into segmental lines which. are connected in series in radial groups and form a sinuous channel for thepassage of the gases or the blast respectively. Each flue of the outermost annular chamber contains an inlet for fuel and another inlet for the air to support combustion. By virtue of this arrangement the heat-exchange area of the air-blast heater is increased conchambers. The economical etiiciency of the heater is thus increased materially. hen

blast-furnace gas is supplied as fuel, the improved air-blast heater offers the furtheradvantage of causing almost the entirety of the stone-vitrifying and other deposit-forming constituents of the gases to be thrown down on the large-surfaces with which the gases come in contact as they pass through the successive fines. The gases issuing from the lastannular chamberare therefore practically free from such constituents. At or beyond the outlet of the last chamber I may therefore provide checkerworlr my means of which the gases ,Will transfer the remainder of their heat to the heat-er, Without any danger of clogging or soiling such checker- Work by the blast-furnace gases. The 3 odically required cleaning of theiiue of the heater presents no difficulty, much as the nested annular. chambers are subdivided into straighf fines.

In the accompanying drawing hare illustrated, as an example of carrying out Specification of Letters Rite-st.

Fatente- Application filed August 31, 1911. Serial No. 6=i$,9r.

my invention, an air-blast heater which blast-furnace gases are utilized as fuel.

Figure 1 is a central ver cal section through the improved air-bi Fig. 2 is a horizontal section taken on line '22 of Fig. l.

The heater shown comprises three annular chambers 1, 2, 3 formed by cO-aXially arranged ring walls 4:, 5, 6, 7 01 difierent disineters, the Walls surrounding one another and also inclosing a central space or well 9which contains checkerwork 8. The annular chamber 3 and the Well 9 are roofed over by a cover or cupola 10, against which abuts an annular cover 11 forming a roof for the chambers l and 2. Bridges 12'and 13 encircle the cupolas or covers 16 and 11 respectively, Which latterare provided with manholes 14 and 15 respectively. Partitions 16 extend radially from the ring wall t to the wall 7, and subdivide the annular chambers 1, 2. 3 into segmental fiues 17, 18 andlt) respectively. The ii 17 communicate with the tines the interior of the cover 11, and -he ii" are connected with the corresponding nues 19 of the chamber 3 by means of openings 20 located at the bottom of the ring wall 6. i'he radial parti l6 ext-end upwardly beyond the walls and 5 to the cover 11, but between the walls 3 and '2', the partitions 16 extend upwardly only to the upper, edge of the inner Wfili In the annular chambers A and 3, the partitions 16 extend downward to the bottom 21. \Vithin the chamber 1 the partitions 16 are not continued to the common bottom 21 of the annular chambers, but leave an annular fr e space 22 at the bottom oi said chamber 1, and with this space r air conduit are connected three pic which, exterioriy oi merged into a sing wall 26 situated a 0s and an upright y-"iindr al axial with the ring cated between the from each i eve, the

eater, and

end-of the central well 9. The outermost ring wall 4 and the covers 10, 11 are surrounded in the well-known manner by jackets 42, 43 and 44 respectively made of iron or the like and arranged out of contact with the masonry work so as to leave insulating air-spaces between them and the masonry. In order'to securegood heat insulation the outer portions of the ring wall 4 and of the covers 10, 11 are preferably made of insulatin bricks (hollow bricks).

W en it is desired to supply heat to the heater, the valves 36 are opened so as to allow the blast-furnace gases to pass from the pipe and the conduit 38 to-the conduits 37 and the chambers 28. From thelatter the gas passes into the flues 17 through the slots 31. The air required to support combustion enters the annular space 22 from the pipes 23, 24, 25, 25 and passes to the same 1 flues 17 from the said annular space 22, by

way of the chambers 29 and slots 32. By making the slots 31, 32 of great length and arrangingv them close to each other a very thorough mixing of gas and combustion air is insured, so that the blast-furnace gas will be consumed quickly and completely over the entire area of the flu'es 17. The combustion products rise in the fines 17 and passing through the interior ofthe cover 11 reach the flues 18 in which said products travel downward to enter the flues 19 through the bottom openings 20. While travellng in a sinuous path through the flues 17, 18, 19, which are connected in series to form radial groups, the combustion gases transfer most of their heat to the walls of said fines, and are also freed almost completely of the suspended blast-furnace dust, which is deposited on the flue walls. From the flues 19 the combustion gases pass into the central well 9, give up the remainder of their heat to the checkerwork 8 and finally leave through the channel 41. After the supply of fuel has been cut off by closing the valves 36, the air-blast to be heated is conducted to the heater through the channel 41 and, flows successively through the well 9 and the fiues 19, 18, 17 in the direction opposite to the flow of the combustion gases during the preceding period or stage. The air-blast, thus heated by a regenerative action, enters the annular space 22 through the slits 32 and chambers 29 and passesout of the heater through the pipes 24, 25, 25*, 23.

With the herein described heater the utilization of heat is very thorough, for the reason that the gases and the air respectlvely are distributed with perfect uniformlty over the entire cross section of the heater, and for the further reason that the draft conditions, path length and resistance are identical for each radial group of seriesconnected flues 17, 18 and 19. a

An important feature ofmy invention is the direct connection of the air and gas to the outermost chamber, or in other words, the arrangement of the combustion chamber at the outer part of the heater. This resents the advantage that the hottest com ustion products are distributed over the largest area or cross section, and as the combustion products cool off, they travel toward the center of the structure and pass through channels of smaller cross section. The combustion products therefore have a relatively slow motion where they are hottest, and a higher speed where they are cooler. The apparatus will therefore become heated much more effectively than with the usual arrangement in which the combustion gases travel from the central space to the outermost chamber. During the heat-absorbing period my heater is also of high efiiciency, since the air to be heated travels first at a relatively high speed, which however decreasesas the air travels from the central space through the several chambers, the air traveling slowest in the outermost chamber 1 which has the largest heating surface. a

The duty of each individual set or group of fiues can be regulated accurately by means of the slides 33, 34 and valves 36, thereby preventing a'prematur'e wearing out of portions of the heater. Since some of the sets of fiues are nearer to the pipes 24, 25, 25' than other sets, it will be obvious that a greater proportion of hot or cold air will tend to pass through the lines which afford a shorter path. This tendency is counteracted by a proper adjustment of the slides 34, opening passages of a larger cross section for those flues which are farther away from the pipes 24, 25, 25, than for those which are adjacent to said pipes. Thus, notwithstanding the fact that the several sets of flues are at different distances from the pipes 24, 25, 25, the flow of hot or cold air maybe regulated in such manner as to secure'a practically uniform distribution of hot or cold air among the several sets of fines. The valves 33 36serve a similar purpose to equalize the supply of gas to the several flue groups, notwithstanding the fact that saidflue groups are at different distances from the pipe 40. The flues being straight, they are cleaned readily'through Lou of fines comprises a segmental line in *ated between the Walls 4 and '5, an adj acent tiue located between the Walls 5 and 6, and a third fiuelocatea between the Wall. 6 and '7. All the fines of the same ra i group communicate groups, between one end or inlet and the other end or outlet of such path or group.

While I have shown ring walls 4, 5, 6, 7 of circular cross section, this is not essential. to

my invention, as I may give these Walls dif-' t'erent cross sections, for instance oval or polygonal. These modifications and others may be made Without departing from the nature of my invention as set forth in the appended claims.

I claim: 1

l. A heater comprising Walls forming nested chambers and partitions extending outwardly through said chambers and subdividing them into lines, the adjacent mes of the several chambers being connected in seriesloy individual connections to form grouoof fines constituting a sinuous path,

each of these paths, between its inlet and its outlet, being entirely separate or disconnected from the other paths or flu-e groups.

2. A heater comprlsing Walls rorming .n'ested chambers and partitions extending segmental outwardly through said chambers and subdividing them into flues, the adjacent lines of different chambers being connected in series to form a group of lines constituting a sinuous path, the individual lines of the outermost chamber being; each provided with separate inlets for fuel and for air to support combustion respectively.

3, A heater cmnprising ring Walls :torru in nested co-axial annular chambers and radial Halls subdividingsaid chambers into segmental fines, the adjacent fines of the several chaua tiers being connected in series by individual connections-to form a'radial group of flue. constituting a sinuous path, each of these paths, hctween its inlet and its outlet, being entirely separate or discoimccttd from the other paths or fine groups.

heater comprising ring; Walls torminfr nested co-aXial annular chambers and radial Walls suhdividingsaid chambers into the adjacent dues of a w r". z n .aimolcs 14, lo and. 35. been setor eparate or dis; connected from the other paths or fine to t the several groups and having, i; i an .0! ,UUOBS with such outermost. lines, one. means for regulating said connections indiv dually.

6. A .heater comprising Walls forming nested surrounding a central space. and partitions subdividing said chambers into tines, the fines of the innermost chamhcr communi no with said central space, and the adjacent of the several chambers being connect alternately atopposite ends, a conduit extending adjacent to the outermost lines of the several groups and having individual connections with such outermost lines, a pipe connected with said conduit, and means for regulating said connections vidually, whereby a Wider may he provided in those connections which are at a greater distance from the point Where said pipe connects with the conduit, so as to equalize the flow in the several groups.

7. A heater comprising Walls forming a central space and fines located around said space at ditlerent distances from the center, the innermost 'l'lucs communicating with said central space. and the other lines communicating with the innermost fines in groups,

a 'as conduit and an air conduit extending I acentto the outermost lines of the several ;;IOHPS, each conduit having individual connections with such outermost tlucs.

A heater comprising walls forming a central space and fines located around said space at different distances from the center, the innermost dues communicating with said central space, and the other lines communicating With the innermost flues in groups, gas conduit and an air conduit extending adjacent to the outermost fines of the sevoral groups, each conduit having individual connections with such outermost lines, and means for regulating such connections individually.

9. heater comprising Walls forming a central space a dilucs located around said space at diti'ereut distances from the center, he innermost hues communicating with u: -tral space, and the other lines communicating rith iimermost lines in ice groups, a gas conduit and an air conduit extending adjacent to the outermost flues of the several groups, each conduit having individual connections with such outermost flues and also having a gas connection and an air connection respectively at one portion of its length, and means for regulating individually, the connections of said conduits with the respective outermost fines.

10. A heater comprising walls forming nested communicating chambers surrounding a central space which communicates with the innermost chamber, partitions subdividing said chambers into flues, each of the fines of the outermost chamber being formed at its bottom with two circumferential slits arranged adjacent to each other, and means for supplying air" and fuel respectively to said slits. v

11. A heater comprising Walls forming chambers subdivided into groups of fines connected in series, individual inlet conduits for supplying air to support combustion, to each group of flues, regulating devices controlling the flow of air through the several inlet conduits, and means for supplying fuel to the fiues. 12. An air-blast heater comprising walls forming chambers subdivided into groups ,of fines connected in'series, individual outlet conduits for conveying the hot blast away from each group of flues, and regulating devices controlling the flow of air through the several outlet conduits.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

EDMUND HOHMANN.

- Witnesses:

Gnoucn LiLIn ms'r, Gnonc KRAUSS.

Copies of this patent may be obtained for live cents each, by addressing the. Commissioner; of Patents, Washington, D. G. 

